Is my meter regulator bad?

Mikar

I had an issue with noise coming from I think the gas main or regulator on my meter.

The other day I had Gas Co. out to check Regulator on meter. It was about 0 degrees outside. The guy showed me exactly 6" wc at a test tee outside at the meter directly after the regulator. At the time my furnace was firing. Guy didnt think the regulator was making the noise and said I was all good on the outside.

Today is only slightly warmer outside and I had my HVAC guy test inlet and manifold pressure at my furnace valve. He was showing exactly 7" wc at the inlet with the furnace firing and 3.5" at the manifold.

Why wasnt the inlet consistent with the gas co. reading outside the other day?

Is the regulator suspect?

Jamie Hall

Gas pressure on the street can vary quite widely, depending on demand and a host of other factors. Which is why you have a regulator...

Mikar

i was thinking the regulators were specifically set to 7", im guessing now there is a range.

And then on the appliance end, there would be no play... once set to 3.5" is should stay there.

Are my assumptions correct?

pecmsg

Yes

Mikar

The tag on my regulator says 3"-7". What happens if the demand is so great that it only supplies 3"? Does the appliance bump it up to 3.5"? Likewise my furnace manual states it takes inlet of 4.5-10.5... so what happens if it doesnt get 4.5"?

Please excuse me if i come off as an idiot, im just trying to understand.

mattmia2

There is also some pressure drop in the meter and the piping that varies with flow, so at the outlet of the meter the pressure will be higher with no flow than with a large appliance operating.

Jamie Hall

Mikar said:

The tag on my regulator says 3"-7". What happens if the demand is so great that it only supplies 3"? Does the appliance bump it up to 3.5"? Likewise my furnace manual states it takes inlet of 4.5-10.5... so what happens if it doesnt get 4.5"?

Please excuse me if i come off as an idiot, im just trying to understand.

Not an idiot. Why would you know, unless you knew? The tag on the regulator gives the input pressure range which it can handle -- in this case, 3" to 7". That would be the street pressure going in. If it is set to put 3.5" out, it will do so -- provided two things: the street pressure must be at least 3.5" plus a give, since it can't increase the pressure, only reduce it to its setting -- and provided that when it tries to produce the regulated pressure there's enough gas in the street to feed it. Which there may not be, particularly in colder weather.

Now in the second question -- that depends on whether there is a second regulator on the furnace. If there is, it works the same way -- so long as it gets enough gas at at least 4.5", it will regulate properly.

Now... if the furnace burner requires 4.5", and the street regulator is set for 3.5" -- problem. The furnace won't be getting the gas it needs and combustion, efficiency, and heat output will all be poor.

ch4man

more than likely the gas co guys or your technicians manometer was off a bit.
the lowest street pressure provided by natural gas utilities is 6" (class 1). if you live on a street with class 1 you wont have a regulator on the meter set.

Mikar

Thanks for the explanations.

So when the regulators fail, what occurs? No pressure, hi pressure, gas flows thru vent instead?

EBEBRATT-Ed

Depends on the failure.

Dirt or something inside could cause high pressure if the regulator can't close. Broken diaphram could cause gas leak out the vent etcetc